I took the HSR to Tainan a couple of years ago and enjoyed it. Did they discontinue the shuttle train that goes from the HSR to the main station? That's how I got into town from the HSR. Was relatively convenient I thought. I agree it is a lot of temples, but for sure some important historic places. I took a morning train from Taipei, overnighted in Tainan and took a late afternoon train back to Taipei.